All Questions
98
questions
1
vote
1
answer
48
views
Effects of dielectric on force between charged bodies?
The electrostatic force between the plates of a charged isolated capacitor remains unchanged when dielectric fills whole space between plates.
But when we take 2 isolated point charges in a dielectric ...
- 187
0
votes
0
answers
34
views
Is there a $H$-field formed by a uniformly moved, charged ball?
Imagine a charged ball with surface charges. Let it travel with a constant velocity $v$.
Imagine a point outside the ball. Since the charge is moving, there is a electric displacement displacement ...
- 363
0
votes
1
answer
35
views
Potential of an alternating electric field in a capacitor
My question comes from a problem of electrodynamics where there's a relativistic particle with a given 4-momentum ($p^\mu=(\varepsilon,\vec{p})$) which enters a capacitor with an alternating electric ...
1
vote
2
answers
275
views
Electric field is produced by the changing magnetic field and not by charged particles according to coulomb's law or Gauss's law?
In my physics textbook, Concept of physics by H.C. Verma, in the section on "Induced electric field", the statement below is written (p. 291):
Electric field is produced by the changing ...
user363762
2
votes
0
answers
57
views
What exactly is induced electric field, Is it present only in conducting loops? [duplicate]
In my textbook it is written that : The presence of a conducting loop is not necessary to have an induced electric field. As long as $\vec B$ keeps changing, the electric field is present. If a loop ...
user376280
-1
votes
1
answer
92
views
No limits of integration for electric field integral?
For this problem,
The solution is,
However, why have they not included limits of integration? I think this is because all the small charge elements dq across the ring add up to Q.
However, how would ...
- 49
0
votes
0
answers
43
views
How to connect $x$, $y$ component of 2D electromagnetic wave equation?
I want to solve following Maxwell's equation.
$$
\triangledown ^{2}E+\frac{\omega^{2}}{c^{2}}E=0
$$
But, Electric field has x, y component in 2D geometry.
So, it will be
$$
\frac{\partial^{2} E_x}{\...
- 1
1
vote
0
answers
54
views
How is $E×B$ zero? [closed]
I was reading Feynman lectures vol. 2 pg no. 291. There I found the general solution of one dimensional planar waves along $x$ direction. My question is the when I apply dot product on $E$ and $B$ ...
- 157
0
votes
1
answer
377
views
Charge in crossed $E$ and $B$ fields
This post describes the motion of a charge in crossed electric and magnetic fields as:
$$
x = r \cos ωt + \dfrac EB t\\
y = r \sin ωt\\
$$
Can you please explain how these equations are derived. Why ...
- 349
0
votes
1
answer
288
views
How to identify north pole of a magnet using only a battery, and a copper wire? [closed]
I have a magnet, a copper wire, and a battery. I need to find the north pole, and the south pole of a magnet using only these items. (not a compass).
Here's my attempt: create a circuit, battery is ...
0
votes
1
answer
42
views
Which configuration is better for this electric motor?
I have a problem with this exercise, it's an electric motor.
an electric motor works because of a magnet, and a wire with a current (i.e electrons moving in it). by turning on and off the current it's ...
1
vote
3
answers
1k
views
Vector potential due to a spinning spherical shell with a non-uniform surface charge distribution
In Griffith's Introduction to Electrodynamics 4th edition example 5.11 the solution for the vector potential of a uniformly charged spinning spherical shell is given.
Now let's assume that the ...
- 439
2
votes
1
answer
393
views
Spherical cavity inside a uniformly magnetized material VS uniformly magnetized sphere
In Jackson 4.4, boundary value problems in dielectrics page 159, a simple relationship is shown between the electric potentials and hence between the electric fields of a spherical dielectric and ...
- 439
1
vote
0
answers
261
views
Magnetic field due to circular surface current density
I am trying to find the magnetic field between two coaxial cylindrical shells of radius $a$ and $b$ respectively. They have a surface current density of $K = K_0cos(\theta)\hat{\theta}$ and $K=-K_0cos(...
- 314
0
votes
2
answers
53
views
Electric field of a configuration of five parallel infinite slabs of dieletric materials [closed]
I am having a hard time trying to figure out how to proceed in order to calculate the electric field of a configuration of five slabs of dieletric (insulating) material (actually one of those is ...
